Is soft PVC more durable, or is rubber more durable?

PVC is not rubber at all, it's plastic. Plastic is generally hard and rubber is generally soft, but this is not absolute, PVC soft rubber is a special case. It is because PVC soft rubber feels like rubber, in fact, it is not rubber at all. Rubber is divided into natural rubber, styrene butadiene rubber, neoprene rubber, neoprene rubber, nitrile rubber, silicone rubber, etc., nearly 20 kinds. Rubber is a kind of polymer material. High elasticity at room temperature is a unique characteristic of rubber materials that is not found in any other material, which is why rubber is also known as an elastomer. Highly elastic materials exhibit large elastic deformations, up to 1000%, in response to external forces, and quickly recover from deformation when the force is removed, compared to about 1% for metallic materials with universal elasticity. 

What is rubber?

Rubber is a material that can be modified to quickly and vigorously recover its deformation in response to large deformations. Modification essentially means vulcanization. Raw rubber, i.e., rubber that has not been cross-linked, consists of linear macromolecules or macromolecules with branched chains. With the change of temperature, it has three states, i.e. glassy, elastic and viscous-fluid. Unvulcanized rubber becomes hard at low temperature and soft at high temperature, without the ability to maintain shape and mechanical properties are low, basically no use value, must be vulcanized to use. That is to say, raw rubber needs a series of processing to be made into useful rubber products, which will have a rubber processing industry. The processing of PVC does not require vulcanization. If you light it with fire, PVC turns to liquid, while rubber only turns to ash. From this appearance it is easy to separate them. Also, rubber is mostly an industrial product. Only a few of them are used in daily life. For example, tires, hoses, tapes, sealing products, vibration damping products and so on.